Answer:
D. Ni²⁺
Explanation:
We know at once that the answer cannot be A or C, because Ni and Cu are already in their lowest oxidation states.
The correct answer must be either B or D.
An electrolytic cell is the opposite of a galvanic cell. In the former, the reaction proceeds spontaneously. In the latter, you must force the reaction to occur.
One strategy to solve this problem is:
- Look up the standard reduction potentials for the half reaction·
- Figure out the spontaneous direction.
- Write the equation in the reverse direction.
1. Standard reduction potentials
E°/V
Cu²⁺ + 2e⁻ ⟶ Cu; 0.3419
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
2. Galvanic Cell
We reverse the direction of the more negative half cell and add.
<u>E°/V
</u>
Ni ⟶ Ni²⁺ + 2e⁻; 0.257
<u>Cu²⁺ + 2e⁻ ⟶ Cu; </u> 0.3419
Ni + Cu²⁺ ⟶ Cu + Ni²⁺; 0.599
This is the spontaneous direction.
Cu²⁺ is reduced to Cu.
3. Electrochemical cell
<u>E°/V</u>
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
<u>Cu ⟶ Cu²⁺ + 2e⁻; </u> <u>-0.3419</u>
Cu + Ni²⁺ ⟶ Ni + Cu²⁺; -0.599
This is the non-spontaneous direction.
Ni²⁺ is reduced to Ni in the electrolytic cell.
20 cups of flour, 30 eggs, and 10 cups of sugar
0.4M is the concentration of a solution formed when 4.00 grams of sodium hydroxide is dissolved to make a 250cm cubed solution.
Molar concentration, also known as molarity, quantity concentration, or substance concentration. Molarity is a unit used to describe the amount of a substance in a solution expressed as a percentage of its volume. The number of moles per liter, denoted by the unit symbol mol/L or mol/dm³ in SI units, is the most often used unit denoting molarity. Because the volume of most solutions very minimally changes with temperature owing to thermal expansion, using molar concentration in thermodynamics is frequently not practical.
The formula for molarity,
Molarity = (moles/vol) x 1000
=
x 1000
= (0.1 / 250) x 1000
=0.4M
Learn more about molarity here:
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Answer:
they are eamples of chemical properties
Explanation:
flammibility is the chemical makeup of the element that makes it flamable and reactivitie is the chemical makeup of an element that is able to reacte to another element